Propeller and paddle-wheel shaft



UNITED STATES PATENT OEE-ICE.

WILLIAM PETERS, OF BALTIMORE, MARYLAND.`

PROPELLER AND PAnDLE-WHEEL SHAFT.

Specification of Letters Patent No. 26,290, dated November 29, 1859.

To all whom 'it may concern:

Be it known that I, WILLIAM PETERS, of the city of Baltimore, in theState of Maryland, have invented a new and useful Improvement inConstructing Propeller and Paddle-lVheel Shafts; and I do hereby de-`clare that the following is a full and exact description thereof,reference beinghad to the accompanying drawings and to the letters andmarks thereon.

The object of my invention is to construct a shaft for propellers andpaddle-wheels which in case of sudden and violent strain, such as theshafts of ocean Steamers are subject to, will not be liable to cross ordirect fracture and the entire separation of the fractured ends from4each other, as It is well known `has often occurred when the shaft wasmade entirely either of wrought or cast metal. The evil sought to beovercome by my invention has been essayed in constructing compoundshafts in which wrought iron rods or bars, placed longitudinally orotherwise, have been surrounded with cast iron. The efforts in thisdirection have not, however, been successful, and in violent strainssuch shafts have usually yielded in the line of direct fracture.

The principle upon which my shaft is constructed, as will readily beseen, is opposed to direct fracture, as the strain is necessarilydistributed and removed from the line of its force, z'. e., from theline of direct fracture at right angles to the line of the shaft.

The drawings forming part of this specification show how I carry out myinvention.

Of these drawings Figure l is a longitudinal section of a complete shaftwith the bearing ends for the molds attached; Fig. 2, being a side viewof theshaft showing the broadest surface of one of the threads formedupon the periphery of the inner part or portion of the shaft, and Fig. 3showing the interrupted 0r .broken condition of the'same thread byforming of other threads.

This improved shaft is made up of wrought and cast metal, or it may bemade entirely of cast metal. When made of cast metal I prefer lthat themeta-l of the exterior Aportion of the shaft shall be different fromthat forming the interior part. Having se- Y lected the material ofwhich to make the letter (a), I have cut upon it, as shown by i thedrawings, `four screw threads, which threads in case this interior partbe of cast I metal can be formed when this part iscast by the processknownxas casting Screw threads?"` In turning `these threads `upon thewrought metal interior the first thread is made continuous from right toleft the r entire length of the interior shaft, the sec-` ond threadlikewise continuous fromleft to right, while the third andfourth aremade in the character of right `and left handedll threads, eachcommencing at` one end ofthe shaft and termin-ating atl the center orhalf the length. The twofirst named threads, by` the drawings are shown`by the yellow coloring and the two latter bythe blue coloring.

`Having this portion of the shaft thus `prepared it is placed in themold for thef cast-` ing around it the exterior portion. The ends of theshaft beyond` the yellow colored part of Eig. 1, and beyond 'uit` dottedunes or Figs. 2 and 3, represent the bearing part y which in the moldand` which `are removed `80 on finishing the shaft. It is understoodthat the molds will have beenprepared for the placing in them thisinterior part of the shaft. The exterior part is then formed by runningin the molten metal upon and around the interior portion.` This exterioror the interior may befwroughtiron and the exterior cast iron. A Shaftconstruct-` ed in this manner will 1 in case of, strain have a uniformdistributionof `the force in the direction of itslgthandwillsuccessfully resist fractures in a line at right angles to itslength. y

It is` evident that this construction is susceptible of being used inmaking other articles than propellers and `wheel shafts, as it may beextended to mill spindles, pieces of ordnance, and other shafts where 1tis de` sirable to provide aga-inst` force exerted in opposing directionsto the line of the Shaftgj Having thus set out my invention what I claimas new and desire to secure by Let--` ters Patent is- A propeller orpaddle-wheel shaft constructed as herein set forth.

Witnesses:

JOHN S. HOLLINGSBEAD,

W. S.` CIIARY.

wM. PETERS. i

